Laser diodes in general comprise a body of a semiconductor material having an active region and regions of opposite conductivity type on opposite sides of the action region. When a voltage of sufficient magnitude is placed across the active region, carriers of opposite conductivity type move into the active region where they recombine to generate light. By forming the regions on each side of the active region of an appropriate material and by providing mirrors at the ends of the active region, the light is confined to the active region where it flows back and forth between the mirrors to form laser light. At least one of the mirrors is made partially transparent so that some of the light will be emitted as a substantially coherent beam of light. Because of its small size and relatively low operating power as :compared to other types of lasers, laser diodes are being more generally used in various electro-optical systems, such as optical communication systems. However, one problem with regard to the use of a laser diode in an optical circuit is that laser diodes inherently operate in the transverse electric (TE) mode, and many devices used in optical circuits operate in the transverse magnetic (TM) mode. Presently such circuits are provided with devices which will convert the TE mode beam from a laser diode to the TM mode where necessary. However, this makes the circuit more complicated and more expensive. Therefore, it would be desirable to have a laser diode which can be easily and quickly switched between the TE mode and the TM mode.